Water-steam mixing valve



Feb. 23, 1954 DAHL ET AL 2,670,003

WATER-STEAM MIXING VALVE Filed Jan. 3, 1952 ATTORNEYS.

Patented Feb. 23, 1954 UNITED STATEd 'iiNT OFFICE WATER-STEAM MIXING VALVE Edward T. DahI, Warwick Neck, and Otto Kneisel, Cranston, R. 1., assignors to Hammel-Dahl Company, a corporation of Rhode Island Application January 3, 1952, Serial No. 264,784

Heretofore a device of this character, which.

may be termed a mixing valve, in use is frequently subjected to considerable change of pressure of. the water which is supplied or in pressure of the steam which is supplied. Accordingly there isv a varying flow of water due to the varying pressure which serves to fluctuate the temperature in the final result. The variation in the flow of the steam may be throttled by a variation in. the line which is found to be a simpler means of controlling the device than by adjusting the spring which operates a valve for controlling the steam.

This invention in its broad aspect contemplates a device for admixture of two fluids which are supplied under pressure andin which the pres-' sure of one of said fluids is subject to vary at different periods and the other held at a reasonably constant pressure. As by way of example, one of said fluids may be cold water supplied from a municipal water supply. The pressure at which said water is furnished is subjected to variation at different periods of the day, the other. fluid to be mixed with the water being steam, the pressure of which may be held reasonably constant.

Qne ofthe objects of this invention is to'provide a movable part which will fluctuate in ac-. cordance with the flow of cold water and which in turn will actuate the steam valve to vary the amount of steam. which enters the cold water.

Another object ofthe invention is to so characterize the valvewhich controls the steam that the steam will enter in proportion-to the flow of water so that thepercentage of steam and water which are mixed. together will. be substantially constant.

Withthese and other objects. in view, the invention consists. of certain novelieatures of construction, as will be more fully described, and particularly ponited out in the appended claims.

In the accompanying drawings:

Figure 1 is a diagrammatic view showing the unit of this invention as connected in use;

Figure 2 is a sectional view-through the device;

Figure 3 is a sectional view on line 3--3 of Figure 2;

Figure 4 is a iragmental view in section of a portion of Figure2;

Figure 5 is a sectional view on line 5-5 of Figure 2;

Figure 6 is a sectional view on line 6-5 of Figure 5; and

'Figure 7 is a sectional view on line- 1-1 of Figure. 2.

In the present embodiment of this invention,

11 Claims. (Cl. 137-98) we arrange to control the flow of the constant. pressure fluid by means of a piston-operated valve and use any convenient device responsive to. change in the velocity of the flow of. another fluid, due to varying pressure, to control the movement of said piston. This device in the in stant application may be a Venturi tube. The throat of the Venturi and the flow thereto are connected across the said piston, providing a differential pressure condition responsive to changes in velocity of flow therethrough to act on said piston in a direction tending to move the piston and the said resultant force will movethe piston to close the said valve to proportionally decrease the volume of the other flow and thereby maintain the predetermined ratio of fluid mixture. Additionally, a metering arrangement is provided on the said valve which, conjointly with the edge of the valve seat, provides for metering the flow through the valve to maintain an accurate constant ratio of said fluids to be admixed. In a like manner, upon an increase in the flow rate of the fluid of varying pressure, the differential pressure across the piston tending to move the valve will increase to overcome the said resistant force and will thus move the piston in a direction to move the valve to the open position.

Referring to the drawings for a more detailed description of the invention, Ill (Figure 3) designates a device operable for mixing water and steam to furnish hot Water for industrial purposes andcompris'es a valve casing H having a water inlet port I2, a steam inlet port l3, and a hot water discharge port I4. Water and steam entering the valve casing through their respective ports will through suitable conduits meet and mix to be discharged through the port l4.

The flow of water through the device is initially regulated to provide a predetermined flow of water at a predetermined delivered temperature. A valve designated generally 15 (Figure 2) is employed for this purpose and is built within the casing H and may be of any suitable type, that shown being of a simple plug construction having a cylindrical body it provided at one end with a blade I! which is disposed. diametrically of the body It with its edges extending in con tinuation of the sides of the said body 16-. The

blade i! has a central opening 48 therethroughi The other end of the body lE-is reduced toform a stem l9 providing a shoulder 20. The end of its outer end portion as at 23.

to the bottom of the bore 24. The bore 24 inwardly of the body it communicates with the port !2 by means of an opening 25 (Figure 3) extending laterally through the side Wall of the said bore 24 and in axial alignment with the port 12. The blade ll extends completely across the opening 25. The bore 243 communicates with the discharge port it through a similar sized opening 25 which extends through the side wall of said bor 25 and diametrically opposite and in axial alignment with the said opening 25 to open into a chamber designated generally 27, into which the said discharg port it opens.

The valve i is secured in position by means of a plug which is externally threaded at each end portion and is provided with a flange 29 at a position substantially centrally thereof. The periphery of said flange may be shaped to receive a wrench. The plug 2-8 is threadingly received within the bore 22 to engage the shoulder 20 and is also provided With a central bor 30 through .251

which the stem i 9 passes to rotatably engage the walls of the said bore. The stem is sealed against leakage by a stuffing box like arrangement comprising a compressible seal washer 3i engaged by a member 32 having threaded engagement with an enlarged portion 33 of the bore 39. Sufidcient pressure will be applied by the member 32 on said seal 31 to deform the sam into tight sealing engagement with the walls of said bore and said stem. The plug 28 is sealed against leakage maximum and that by turning the valve to any of various positions relative to openings 25 and 26, the efiective size of said openings 25, 26 may be varied to regulate the flow of water through the device Ill. There will be a minimum flow through the valve by flow through the opening I8 at closed position of the gate H. In practice, the valve [5 is adjusted by turning the stem 19 (Figure 2) such as by means of a screwdriver engaging the slot 25 to provide for a preset desired flow through the device in accordance with the steam supply available to furnish hot water at a predetermined temperature. To prevent readily unauthorized adjustment of said valve 15, a closure cap 34 is threadingly received on the outer end of the plug 28 to enclose the stem 59.

i The steam port I3 and chamber 21 are separated by a solid bridge portion 35 which has a threaded opening 35' therethrough. An externally threaded bushing 35 is threadingly received in said opening 35 and provides an, opening 31 or steam passage into said chamber 2?. ing is controlled by means of a valve which is designated generally 33 and comprises a tubular body 39 (Figure 4) having an annular flange 4t spaced from the inner end of said body 39 and adapted to seat against the marginal edge 3'! about said opening 31 to close the same against the passage of steam therethrough. The said inner end of the valve 38 is partially closed by a wall 4| having a central opening 42 therethrough.

The open-- The body 39 is slidably received in a valve receiving member 43 which is threadingly received in an opening 44 extending through a side of the casing H (Figure 2) and axially in line with the opening 3? and communicating with port l3. The plug has a flange 45, the periphery of which may be shaped to receive a wrench to tighten the plug in place. A gasket 46 may be interposed between the flange and the casing H to seal said plug against leakage. A pressure balanced pilot valve designated generally 4? is positioned within the body 39 and comprises a sphere or ball 48 which is resiliently urged into engagement with the edges of said opening 42 to complete the closing of the upper end of valve 38 by means of a compression spring 49 acting between said ball 48 and a plug abutment 50 which is received Within the body 39 and secured thereto for movement therewith as by means of a pin fastening 5!. The abutment 5B is made hexagonal in cross-section so as to provide passages 52 to the interior of said body 39 inwardly of the abutment 58. A linear or compression spring 53 is positioned to act against the abutment 5B and the bottom of the bore 54 in which the said body 39 is received and tends to normally seat said valve 38 in engagement with the said marginal edge 31'.

Steam entering said port l3 will leak between the body 39 and adjoining wall of the bore 54' and pass inwardly through passages 52 into the interior of the body 39 to act against the ball 48 1 in a direction tending to move the ball to seated position. The effective area on said ball 48 exposed to said steam pressure tending to move the said ball to seated position is that equal to the area of the ball engaged by the edge of said opening 42 when said ball is in the closed position.

As previously stated, water is supplied from a' supply source, such as a municipal water supply, the temperature of which remains reasonably constant. The pressure of said water supply may, however, vary considerably at different periods of the day for reasons well known. It is preferable that the steam be supplied at a pressure which will be substantially equal to the pressure of the water and in amounts predetermined by the desired temperature of the hot water to be supplied. It is also desirable that the flow of steam be quickly responsive to changes in the rate of flow of water through the device. To achieve these results, the movement of valve 38 is arranged to be controlled by the rate of the flow of water and to this end a Venturi tube-like T member 55 (Figure 3) is interposed in the cold water flow by connecting said member 55 to the opening 26 in any convenient manner such, for example, as by threaded engagement with the walls of the opening as at 56. The body of member 55 is provided with a plurality of openings 51 therethrough'into the chamber 2'! to extend to near the junction of the port [4 and said chamber 21. The throat portion of said member 55 is provided with an opening 58 therethrough which connects with a conduit 59 extending to the bottom of a cylinder 60 formed in the said casing I I (see Figures 3 and 5). A piston 6| is mounted for reciprocation within said cylinder and a conduit 12' from the port i2 extends to the upper portion of the cylinder 50 above the piston SI thereby providing for a dif ferential pressure across said piston 5i tending to move the piston inwardly of said cylinder; A, valve operating plunger 52 having a reduced end device as a whole will be readily apparent.

aeria oos;

portion 53 providing a. shoulder--64 (see Figures 2 and-4a. is attached to said piston in any suitable mannerxand projects inwardly thereof through a centralv opening 65 in the bottom ofthebylinder 50. to extend axially in-iinewith thevalve 38 and.

with the said reduced portion 63 projectin through the. opening '42- into engagement with the 'ball- 48. The spring 53 will providea re sistance or opposing forceto the movement of valve 38 proportional to the compression of the spring 53.

Upon the-opening of said device in to theflow of water therethrough, the difierentialpressure established across the piston M will move thepiston 6|. inwardly to initially unseat the ball. closure: 48. The steamv pressure acting on-the ball 48 as previously described will escape through opening 42. and the spring 49-under pressure of.

ball 48iwill collapse andfurther movement of the piston in the.- same direction. will: cause the shoulder 64 on the. plunger '62'to engagethe valve 38.150 move the same from. its seat against the pressure oftherspring 53,-.thus opening'the'valve 38: to-the passage of steam through opening. 31 into chamber 21.. cold waterline, the resulting differential across the'piston 6! will permitv expansion of thespring 53- proportionally to move the valve 38 toward:

movement of the body 39 to obtainany, desiredflow-versus lift" characteristic in accordance-with.

the application in which the valve will be-aused taking into account the normal flow to be expected through ports l2 and I3. Thesurface G6;

conjointly with the edge 61' of the'opening 31- provides for metering the volume of steam pass-:

ing through said opening in proportion to the movement of saidvalve 38.

Steam entering chamber 2T will passthrough openings 51. into the bore-oithetube 55 to mix with the flow of Water. therein by condensation thereof. Steam leaking by plunger 62 into the low" pressure side of the piston 6| will likewise. condense and its pressure dispersed without affecting the difierential across said piston In operation; themixing device maybe posi-, tioned in a typical installation as shown :diagram-- The steam line '10 maybecontrolled by a usual valve ll and a steam reamsingxvalve I2 may also-be positioned-in the -"steamv line to control the-pressureof the steami ltoi the" The waterline" matically in Figure 1.

steam port I3 of the device. may'also-have a control valve 14 therein to control the now ofwater to the port l2 and the discharge port l4 may be connected through a line 15 to service. The detailed operation of the several elements'of the device has'been givenin'connection with. the detailed description of the same, and it is believed the operation of the ltwill now be apparent that wehave disclosed a mixing device for two different flows in which one of the flows controls theotherflow and which uponiailure of the saidxoneflow, the othen'flow is automatically. shut oil.

Upona-drop in pressure in the: =1.

We claim:

1. A-device torrcontrolling'the iflowzoinsecondi fluidfor affecting the admixture of said-second:

fiuidiwitha first fluid in predetermined amounts:- to said first fluidacomprising a mixingxchamber; a passage for the-flow'ofrsaid first fluid'tosaid' chamber, a passage for the flow of the:

fluid to said chamber, a piston-operated valve:

for controlling. the passage for the flow of: the

second fluid into said chamber; and means eluding a restriction-in-theflrst passageto create a difierential. pressure, said: pressure transmitted across said. piston tending to move thesameto:

control the flow of the second fluid.

2 A= device'ror affecting; the admixture ot two: fluids at. a predetermined volume ratio and in:

which one of saidiluids maybe of constant pres sureand the other variable aslto pressure-,oom prisinga housing having walls-.formingxa mixing? chamber, a first passage for the-fluid of varh able pressures. to said chamber, a second passage forfthe fluid of constant pressure. to said chum ber, means including a restriction in saidilrste passage: to create pressure. difierentials in: the

' flow of;fiuidthroughsaidfirst passage in responxel to flow,..avalve formingpart-of saidsecond-paste sage; said valve including a pressure differential responsive device operable'to increase :or deciease the flowof fluid through said seconds-passage and means for connecting the ,pressure difierentiais in. said first passage 1 to i said pressure" differeh'itial responsive device to operatethe' samein accordance with the pressure differentials transmitted thereto.

3. A devioefor affecting'the'admixturaottwo fluids. at a predetermined volume ratio and in: which one ofsaid fluids may be: of constant pressure: and theother variable as: to: rn'essure; comprising a: housing: havingv Walls forming a mixing chamber, a first passage "for the' fluid oi variable pressures to saidchamber, a secondpassage for the fluid of constant" pressureto. said chamber, valve means for controllingthe-second passagmmeans including a restriction forming;

part of saidfirst passageadaptedto create a" pressure differential responsive to the flow of said liquid of .variabl-epressure; said valve-meansincluding .a pressure differential responsive device operable for affecting. the: moving of: said valve means to and iromclosed position, means to transmit pressure derived. from" one point alongsaidrestriction. of; the flow of fluid oi vari-- able pressure said first passage'to the pressure differential 1 responsive device, :and means. to

transmit pressure derived from: another point along said restriction-in said-first passage to said pressure differential responsive device whereby said pressure differential responsivedevice willoperate to afieotclosing andopeningofLsaid-valvei. means in accordance with the pressure :difieren. tials transmitted by said difierential pressure transmittingmeans 4. Adevicefor afiecting the admixture ofitwo fluids ata predetermined ratio and in which one. of saidafluids may be of constantv pressure and the other variable as to pressure, comprising) a housing having walls forming a mixing chain. ber, a first passage for'thefluidof variable pres-- sures to said chamber, a second passage for the fluid ofconstantpressure to said chamber. valve means for controlling the second passage. a

Venturi. tube:- forming part of. saidvflrst passage,-

saidvalve means inclhdinga pressure-diflerene tiaL responsive device=- operable for. effecting the moving of said valve means toandstrom closed:

position, means to transmit pressure derived from one point along said Venturi tube to said pressure responsive device and means to transmit pressure derived from another point along said venturi to said pressure responsive device whereby said pressure difierential responsive device'will operate to affect closing and opening of said valve means in accordance with pressure difierentials transmitted by said differential sure transmitting, means.

- 5. A device for afiecting the admixture of two fluids at a predetermined ratio and in which one of said fluids may be of constant pressure and the other variable as to pressure, comprising a housing having Walls forming a mixing chamber, a first passage for the fluid of variable pressures to said chamber, a second passage for the fluid of constant pressure to said chamber, valve means for controlling the second passage, a Venturi tube forming part of said first passage and having a throat portion and a larger portion extending into said chamber, said larger portion extending into said chamber having a plurality of openings in the wall thereof for the passage into said lar er portion of the other fluid entering said chamber, said valve means including a pressure differential responsive device operable for eifecting movement of said valve means to and from closed position, means to transmit'pressure from the upstream side of said Venturi tube to said pressure diiTerential responsive device, means to: transmit pressure from the said throat of the'venturi to said pressure differential responsive device whereby said pressure diiierential responsive device will operate to effect closing and opening of said valve means in accord-- ance with pressure differentials transmitted by said differential pressure transmitting means.

6. A water and steam mixing device comprising a housing having Walls forming a mixing chamber, a first passage for the water to said chamber, a second passage for the steam to said chamber, means forming a restriction in said first passage to create pressure difierentials in the flow of water through said first passage, a flow controlling means forming part of said second passage, said flow controlling means including a pressure differential responsive device operable to increase or decrease the flow of steam through said second passage, means to transmit pressure derived from one point of the flow of water in said first passage to said pressure dif-- ierential responsive device, means to transmit pressure derived from another point of the flow of fluid in said first passage to said pressure differential responsive device whereby said pressure differential responsive device will operate to efi'ect the said increase or decrease in the flow of steam iri'acco'rdance with the pressure differentials transmitted by' said transmitting means".

'7. In a water and steam mixing device, a mixing chamber, a water conduit to said chamber,

a steam conduit to said chamber, valve means for controlling the steam conduit including a valve seat forming part of said steam conduit, a spring pressed closure for said seat, a plunger for engaging said closure, a piston carried by said plunger and movable to move said closure from said seat. means incorporated in the water conduit and forming part thereof adapted to createpressure differenti'alsin the flow of water in said-water conduit, means to transmit pressiire derived from one point of the flow of water in said conduit to one side of said piston, and

pres-'- means for transmitting pressure derived from:

another point of the flow of water in said water conduit to theother side of said piston whereby said piston will be moved to move said plunger in a direction in accordance with the pressure diiierential transmitted across said piston.

8. In a water and steam mixing device as set forth in claim '7 wherein said means adapted to create pressure differentials in the water conduit is a Venturi tube.

9. In a water and steam mixing device, a houssaid pressure from the steam conduit acting on said valve member, a closure for said vent conduit, means for initially moving said closure to:- open position and thereafter moving said valve member to open position, said means including a pressure differential responsive device, means forming part of said water conduit and adapted to create pressure difierentials in the flow of water through said Water conduit, means for transmitting pressure derived from one point 01 the flow in said water conduit to said pressure differential responsive device and means 'for transmitting pressure derived from another point of the flow in said water conduit to said pressure differential responsive device whereby the same will operate to efiect moving of said closure to open position and said valve member from said seat in accordance with the said pressure difler entials transmitted.

10. In a water and steam mixing valve device as set forth in claim 9 in which said valve mem-. ber is'shaped so as to control the flow in propor-' tion to the linear movement of the valve from its seat.

ll. A device for controlling the flow of a second fluid for affecting the admixture of said second fluid with a first fluid in predetermined amounts to said first fluid, comprising a valve casing, a mixing chamber, a passage for the flow of the said first fluid to said chamber, a passage for the flow of the second'fluid to said chamber, a valve for controlling the passage for the fiow of the second fluid to the chamber, a

control means for said valve comprising a cha'm ber along the actuating stem for said valve, said chamber having movable means therein to divide the chamber into two parts, said movable means being coupled to the valve actuating stem, restriction means in said first passage to create a pressure differential in response to the flow Off fiuid'therein, "said pressure'diflerential being transmittedacross said chamber dividing means to move the same and control the flow of the second fluid.

EDWARD T. DAHL. OTTO KNEISEL.

References Cited in the flle of this patent UNITED STATES PATENTS Number Name Date 2,009,102 Bern July 23, 1935 2,064,244 Davies et al Dec. 15, 1936 r f FOREIGN PATENTS Number. I Country Date 658,787 Germany Apr. 12, 1938.1 

